Examples for an entity reference used in an attribute value
(note that within replacement text put in a double-quoted value literal
in a declaration, a verbatim single-quote character can be used
unquoted; likewise, within a single-quoted value literal,
a verbatim double-quote character can be used unquoted;
otherwise, single- or double-quote characters as verbatim
text are specified as character entity reference within
quoted literals); expansion into attribute value encodes
single and double quote character in the replacement text
into character entity references